Conventionally, clothes produced from a fabric having mixed therein a hygroscopically heat-generating fiber such as cellulose and capable of generating heat upon insensible perspiration or sweating from a human body wearing the garment are known as clothing exhibiting a temperature rise during wear, such as thermal clothing (see, for example, Patent Document 1). However, when the moisture absorption amount of the fiber reaches saturation, the hygroscopically heat-generating fiber does not generate heat any more and not only the heat generation time is short but also after the moisture absorption amount reaches saturation, the wearer may feel cold due to water in the fiber. Furthermore, as a heat-generating fabric and a heat-generating garment utilizing other than heat generation by absorption of moisture, it is known, for example, to incorporate a heater such as sheet heating element and linear heating element into the clothing, but in all cases, heat is generated by electricity, and the garment is heavy and requires an electrode, resulting in a garment that hinders smooth movement.
In this way, clothing rising in temperature during wear, which is comfortable and lightweight, is found nothing other than hygroscopic heat generation, but a hygroscopically heat-generating fabric is bound by the restriction of absorbing moisture and therefore, is limited in its hygroscopic heat generation. Thus, comfortable lightweight clothing capable of permanently generating heat when worn as a garment has not been discovered.